Device and process for the handling and control of the yarn in a crosswinding head of a crosswinding machine in bobbin doffing operations

ABSTRACT

The invention relates to a device and a process for the handling and control of the yarn ( 1 ) in a crosswinding head of a crosswinding machine in bobbin ( 2 ) doffing operations, said crosswinding machine being equipped with a series of crosswinding heads and at least one service trolley ( 13 ), in which the yarn ( 1 ) run is moved to a definite position, near the end portion of its course from the pirn to the bobbin ( 2 ) and the yarn ( 1 ) is subsequently drawn from a handling device ( 12 ) of the service trolley ( 13 ), cut and, after removal of the bobbin ( 2 ), its end coming from the pirn, is arranged on a new winding tube.

The present invention relates to a device and process for the automaticdoffing of bobbins in a crosswinding machine, or for the substitution ofa bobbin which has reached the pre-established dimensions, with a newtube around which the yarn coming from a feeding pirn is wound to form anew bobbin.

As is known, the procedure for the formation of a bobbin essentiallyconsists of unwinding operations of the yarn from feeding pirns,cleaning the yarn from possible faults and its crosswinding on tubes,according to forms and dimensions which vary according to thedestination of the yarn. If the yarn is destined for feeding high-speedmachines, the bobbins are normally cylindrical, or truncated-conicalwith a low conicity, if, on the contrary, the yarn is destined forfeeding low-speed machines, the bobbins are truncated-conical with ahigher conicity. The degree of conicity is selected so as to alwaysensure a correct unwinding of the bobbins during their final use, in thepresence of more or less strong centrifugal forces.

A crosswinding machine allows the contemporaneous formation of a seriesof bobbins, i.e. it normally comprises a series of so-calledcrosswinding heads, positioned side by side, and served by at least onecommon service device, also called trolley, which can run along thewhole crosswinding machine, positioning itself in correspondence witheach crosswinding head and which effects, in an automated manner, theoperations which are cyclically required by each crosswinding head.

During the formation of the bobbin it may be necessary to intervene tosubstitute the run-down or faulty pirns, or to substitute the bobbinwhich has reached the pre-established dimensions, with a new tube.

In particular, in the case of bobbin doffing, or if it is necessary tosubstitute a bobbin which has reached the pre-established dimensions,the pirn from which the yarn comes, in turn, not yet being exhausted,the crosswinding head must be stopped in order to be able to dischargethe bobbin and substitute it with a new tube. The yarn coming from thepirn is cut and the end is fastened to the new tube to restart thecrosswinding.

Furthermore, according to the known art, each crosswinding head isnormally equipped with devices, situated along the run of the yarn fromthe feeding pirn to the winding bobbin, which eliminate possible defectsof the yarn and remedy possible breakages. In the case of yarn defects,in fact, said defects must be located, the yarn must be cut, the faultypart eliminated and the two ends, which have formed on the side of thepirn and bobbin, respectively, must be re-joined. In case of accidentalbreaking of the yarn, the disruption of the yarn must be detected andthe two ends of the yarn, respectively from the one side of thespool/pirn and from the one side of the bobbin, must be once againjointed to each other.

It is evident that, along the run of the yarn from the unwinding pirn tothe winding bobbin, in a crosswinding head, devices for detecting thecharacteristics of the yarn must be present, together with devices forcutting the yarn, devices for capturing the ends of the cut (oraccidentally broken) yarn and devices for joining the ends of the yarn.In particular, the capturing devices of the cut yarn ends normallyconsist of two suction mouths, for the collection of the yarn end comingfrom the pirn and from the bobbin, respectively, situated on armsoscillating between a first position, corresponding to the pirn and thebobbin, respectively, and a second position, in correspondence with thedevice for joining the yarn ends, also called joiner or knotter.

The handling and control of the yarn during the bobbin doffingoperations, require the intervention of the common service device which,in cooperation with the devices of the crosswinding head situated alongthe run of the yarn from the feeding pirn to the winding bobbin,recovers the yarn end coming from the pirn, positions the new windingtube and arranges the yarn end on the new winding tube.

It is therefore important to provide for all the necessary expedients sothat all the devices of the different crosswinding heads can cooperatein an optimal way with the common service device, so that the yarncoming from the new pirn is effectively collected by the common servicedevice, which, subsequently, provides for its disposal on the new tube.

According the known art, when it is necessary to substitute a bobbinwhich has reached the pre-established dimensions, the yarn running fromthe pirn to the bobbin is cut to prevent its continued winding onto thebobbin as a result of the rotation inertia of the same. The yarn endsconnected to the pirn and the bobbin are recovered by means ofrespective suction mouths (in particular, for the end wound onto thebobbin, it is necessary to wait until the bobbin has stopped, the bobbinis then rotated in the opposite direction with respect to the windingdirection, until a sufficiently long yarn end is unwound from the bobbinand can be sucked by the suction mouth) and carried by the same to thejoining device, which re-establishes the yarn continuity only at thispoint, as the yarn is not moving, can the service trolley intervene,collecting the yarn by means of a first manipulation device, cutting it,maintaining the end coming from the pirn, then, by means of a secondmanipulation device, removing the bobbin, which has reached thepre-established dimensions, and positioning a new winding tube, whereasthe first manipulation device wedges the yarn coming from the pirnbetween the tube base and the counterpoint of the bobbin-holder arm. Inthis way it is possible to restart the yarn winding operations aroundthe tube, to form a new bobbin.

The above procedure is not very effective as it requires a cutting andsubsequent joining of the yarn before the service trolley can interveneand recut the yarn. This procedure however not only solves the problemof the undesired winding of the yarn around the bobbin, due to therotation inertia of the same, but, above all, it facilitates thewithdrawal of the yarn by the manipulation device of the servicetrolley, which only intervenes when the yarn has stopped. In order toassure a uniform winding of the yarn on the bobbin, in fact, a so-calledcross-winding is effected, using means which guide the yarn with abackward-forward movement along the whole length of the bobbin information. These means can consist, for example, of a so-called drivingor traversing cylinder i.e. which makes the bobbin rotate and havinggrooves on its surface which, while the cylinder is rotating and makesthe bobbin rotate, direct the yarn according to a backward-forwardmovement from one end to the other of the bobbin. Under theseconditions, the difficulty for the trolley to intervene on the movingyarn, due to the continuous movement of the yarn during its winding ontothe bobbin, can be easily understood.

According to alternative solutions of the known art, it was proposed tocut the yarn when the bobbin has reached the desired dimensions, not torecover however the two ends to re-establish the yarn continuity, butonly to recover the end on the pirn side and deliver it to the trolleyto be inserted on the winding tube.

A known procedure for the capturing of the feeding pirn end and itsconsignment to the service trolley, is described in the patent EP1127831 in the name of Schlafhorst AG, and envisages that the yarn endbe collected by an arm equipped with a nipper which delivers it to aseizure and cutting device situated near the joiner. The yarn is cut bythis seizure and cutting device and is collected by a collecting device,from which it is collected by a special supplementary sucking tube whichtransfers the cut yarn to a seizure and cutting device situated in theupper zone of the crosswinding head, wherein the yarn can be easilyreached by the manipulator of the service trolley. This solutionrequires a series of specific devices, in correspondence with eachcrosswinding head, which only operate when necessary.

According to European patent application EP 1236668, in the name ofMurata Kikai Kabushiki Kaisha, a procedure is described wherein the yarnend on the pirn side is collected by the suction mouth which is on theside of the pirn and directly delivered by the same to the manipulatorof the common service trolley. This solution does not require additionaldevices on the crosswinding heads, but it is necessary to equip theservice trolley manipulator with an extendable arm, capable of reachingand collecting the yarn end in a lowered position with respect to thatrequired for its subsequent arrangement on the tube.

In European patent application EP 1428783, in the name of Sauer GmbH, aprocess and a device are described which allow the recovery of the yarnend coming from the pirn, by sucking it with the suction mouth which issituated on the side of the pirn and carrying it to a area crossed bythe run of the suction mouth situated on the side of the bobbin. Afterpositioning the suction mouth which is on the side of the bobbin, nearthe yarn, the suction of the suction mouth situated on the bobbin sideis stopped, whereas the suction is activated of the suction mouth whichis on the side of the bobbin. In this way, the suction mouth on the sideof the bobbin takes delivery of the yarn end. The suction mouth situatedon the bobbin side is then rotated to the position near the bobbin,wherein the yarn is collected by the manipulator of the common servicetrolley. In this way, the intervention of the service trolley isfacilitated with respect to the disclosure of the Murata patent, as itis not necessary to excessively extend the arm of the service trolley,but the exchange efficiency of the yarn between the two suction mouthswhich takes place by deactivating the suction of the suction mouth whichis on the side of the pirn and thus allowing the suction mouth situatedon the side of the bobbin to suck the yarn end, does not guaranteeadequate success, bearing in mind that there can be a considerable yarnlength already engaged by the suction mouth on the pirn side, which cantherefore hinder the sucking action on the part of the suction mouth onthe side of the bobbin. This possibility of error in the consignment ofthe yarn is extremely undesirable as it would jeopardize the restartingof the crosswinding head, thus creating a lack of production.

An objective of the present invention is to facilitate the interventionof the service trolley, in particular its collection of the yarn to beinserted in the new winding tube during the doffing operations of abobbin which has reached the desired dimensions.

A further objective of the present invention is to guarantee a higherproductivity of the crosswinding machine through a higher operatingfactor.

These objectives according to the present invention are achieved byproviding a process for the handling and control of the yarn in acrosswinding machine in doffing operations of a bobbin, as specified inclaim 1, and a crosswinding machine particularly suitable for theembodiment of this process as claimed in claim 12, as well as aparticular suction mouth as described in claim 16.

Further characteristics of the process, the crosswinding machine and thesuction mouth according to the present invention, are described in therespective dependent claims.

The present invention will be now described, for illustrative butnon-limiting purposes, according to one of its preferred embodiments,with particular reference to the figures of the annexed drawings,wherein

FIG. 1 schematically shows some of the devices of a crosswinding headand a service trolley of a crosswinding machine during crosswinding,

FIGS. 2-5 schematically show some of the devices of a crosswinding headand a service trolley of a crosswinding machine during a sequence ofphases of the process for the handling and control of the yarn in bobbindoffing operations,

FIG. 6 shows a suction mouth for the recovery of yarn ends on the sideof the bobbin, which has positioning means of the yarn on its back,according to an embodiment of the present invention.

With reference to FIG. 1, various devices are shown of a preferredembodiment of a crosswinding head during crosswinding operations, and inparticular a yarn 1, coming from a pirn (not shown), which is woundaround the bobbin 2, together with a slit plate 3, a driving andtraversing cylinder 4 and a bobbin-holding arm 5. A suction mouth 6 forsucking yarn 1 ends on the side of the bobbin 2 and a joiner 7, are alsoshown.

Under normal operating conditions, FIG. 1, the yarn 1 which is unwoundfrom the pirn to the bobbin 2 crosses the slit plate 3, which has thefunction of detecting defects of the yarn 1, and, possibly, cutting itby means of a cutting device not shown in the figures, but substantiallysituated in the same position as the same slit plate 3. The driving andtraversing cylinder 4 guides the yarn 1, through a backward-forwardmovement on the whole length of the bobbin 2, so that the yarn 1 isuniformly distributed on the whole length of the bobbin 2. For thispurpose, the surface of the driving and traversing cylinder 4 is crossedby a series of grooves, also called cavities, inside which the yarn 1 ispassed, the same driving and traversing cylinder 4 being maintainedunder rotation.

The function of the suction mouth 6 and of a corresponding suction mouthon the side of the pirn (not shown) is to take up the ends of the yarn1, possibly formed due to the cutting or breakage of the yarn 1 andrespectively connected to the pirn and the bobbin 2, and deliver them tothe joining device 7, which reestablishes the continuity of the yarn 1.

With reference to FIG. 2, according to the present invention, incorrespondence with the detection of the formation of thepre-established dimensions of the bobbin 2, or, in any case, incorrespondence with a command for changing the bobbin 2, the suctionmouth 6 on the side of the bobbin, is moved, by rotating around an axisA, from its rest position to the position near the bobbin 2, withoutactivating the suction. During its movement, the suction mouth 6intercepts the run of the yarn 1, which is forced to pass onto the backof the suction mouth 6.

As an alternative, the movement of the suction mouth can be activated,during the rotation of the bobbin 2 or after stopping it. In this secondoption, the yarn 1 can be cut, the bobbin 2 slowed down and the two yarnends joined, as in the procedure of the known art described above,before starting the movement of the suction mouth 6 on the side of thebobbin 2.

When the rotation of the bobbin 2 is interrupted before the suctionmouth 6 has reached the position near the bobbin 2 from its restposition, the necessary amount of yarn due to the engagement of theyarns itself on the back of the suction mouth, will be taken from thepirn. Furthermore, in order to facilitate the exit of the yarn 2 fromthe grooves of the driving and traversing 4, it may be necessary tomaintain the same driving and traversing cylinder 4 in rotation, afterremoving the connection through which the cylinder 4 transmitted itsmovement to the bobbin 2 in formation.

During the movement phase of the suction mouth 6, the position of theyarn 1 on its back, can be conveniently constrained through positioningmeans. With reference to FIG. 6, in fact, as the suction inlet 8 of thesuction mouth 6 is extremely large (due to the main function of thesuction mouth 6, consisting in recovering the end of a cut yarn from thebobbin 3, said end being at any point of the bobbin length), the back ofthe suction mouth 6 becoming narrower from the suction inlet 8 towardsthe oscillating arm 9, the yarn 1 can be situated in any point of theback of the suction mouth 6 and, during its rotation around the rotationaxis A, in the absence of positioning means, it could also fall to theside.

The positioning means of the yarn 1 are preferably in the form of atleast one draft, situated on the back of the suction mouth 6, V-shapedso that, once the yarn 1 is collected along the arms of the V-shapeddraft, the same tends to converge towards the center of the draftitself. With reference to FIG. 6, even more preferably, the positioningmeans of the yarn comprise two V-shaped drafts, a first draft 10 nearthe sucking inlet 8 of the suction mouth 6, substantially having thesame width as the inlet 8 of the suction mouth 6, and a second draft 11,near the oscillating arm 9, with reduced dimensions. During rotationaround the axis A, in fact, the suction mouth 6 engages the yarn 1 firstwith its portion closer to the sucking inlet 8. Consequently, due to theeffect of the first draft 10, the yarn 1 will have already reached awell-defined position when it engages the whole back of the suctionmouth 6, and consequently the second draft 11.

With reference to FIG. 3, when the suction mouth 6 has reached the endof its run, or with the suction inlet 8 near the driving and traversingcylinder 4, the yarn 2 occupies a well-defined position in the spacebetween the back of the suction mouth 6 farthest away from the suctioninlet 8 and the slit plate 3. In correspondence with this position, theyarn 1 can be reached with great precision by the manipulating device 12of a service trolley 13. In particular, the manipulating device 12comprises a telescopic arm 14, which can rotate around an axis B, atwhose end there is a nipping and cutting device 15.

From an operative point of view, the call signal of the service trolley13 on the part of the crosswinding head during a doffing operation of abobbin, can be sent in correspondence with reaching the pre-establishedfilling degree of the bobbin 2, but also before this, so that theservice trolley 13 is positioned in correspondence with the crosswindinghead before the suction mouth 6 reaches the intervention position of themanipulation device 12. In this way, the devices of the trolley 13 whichare involved in the doffing operations of the bobbin and itssubstitution with a new tube, are ready to intervene the very moment inwhich the suction mouth 6 has reached the intervention position, but thetrolley 13 could be forced to wait.

As an alternative, the call signal of the service trolley 13 can be sentsubsequently, so that the trolley 13 is situated in correspondence withthe crosswinding head after the suction mouth 6 has reached theintervention position of the manipulation device 12. In this way, thetime the service trolley 13 dedicates to the specific crosswinding headfor the doffing operations of the bobbin 2 and its substitution, isminimized, but the crosswinding head could be forced to remain onstandby.

With reference to FIG. 4, once the service trolley 13 and the suctionmouth 6 are in the right position, the telescopic arm 14 extends and thenipping and cutting device 15 collects the yarn 1, in correspondencewith the area immediately behind the back of the suction mouth 6, asdefined by the positioning device situated on said back.

With reference to FIG. 5, the nipping and cutting device 15 subsequentlycuts the yarn 1 and withholds the end coming from the pirn, whereas thebobbin 2, freed by the bobbin-holding arm 5, is moved away.

Still maintaining the hold of the yarn end 1 coming from the pirn, themanipulating device 12 moves away from the crosswinding head, tofacilitate the return of the suction mouth 6 to its rest position.

The subsequent insertion phase of the yarn 1 on the new winding tube,can be completed, at this point, by the manipulation device 12,according to any of the known techniques, which have the common aspectof inserting the end of the yarn 1 between the base of the tube and acounterpoint envisaged on the arm of the bobbin-holder 5.

The manipulation device 12 of the service trolley 13 subsequently leavesthe yarn 1, and it is possible to start the formation of a new bobbin,whereas the service trolley 13 is free to intervene on othercrosswinding heads of the crosswinding machine.

The present invention is described for illustrative but non-limitingpurposes, according to preferred embodiments, but variations and/ormodifications can obviously be applied by experts in the field, allincluded within the relative protection scope, as defined by theenclosed claims.

1. A process for the handling and control of the yarn (1) in acrosswinding head of a crosswinding machine in bobbin (2) doffingoperations, said crosswinding machine being equipped with a series ofcrosswinding heads and with at least one service trolley (13), each ofsaid crosswinding heads comprising a pirn, from which a yarn (1) isunravelled and is wound to form a bobbin (2), around a winding tube, twomouths for the suction of the yarn (1) ends possibly formed, by breakageor cutting, on the side of the pirn or on the side of the bobbin (2)respectively, and for the delivery of these ends to a joining device(7), situated along the run of the yarn (1) from the pirn to the bobbin(2), to re-establish the yarn continuity, said service trolley (13)being capable of running along the whole crosswinding machine, in orderto position itself in correspondence with each crosswinding head andcomprising a manipulation device (12) of the yarn (1) characterized inthat it comprises the following phases: moving of the yarn (1) run in adefined position, near the terminal portion of its course from the pirnto the bobbin (2), seizure and cutting of the yarn (1), incorrespondence with said defined position on the part of a manipulationdevice (12) of the service trolley (13), which withholds the end comingfrom the pirn, distancing of the bobbin (2), arrangement on a newwinding tube of the yarn (1) coming from the pirn and start of theformation of a new bobbin.
 2. The process for the handling and controlof the yarn (1) in a crosswinding head of a crosswinding machine inbobbin (2) doffing operations according to claim 1, characterized inthat it comprises the following preliminary phase: interruption of thewinding of the yarn (1) onto the bobbin (2).
 3. The process for thehandling and control of the yarn (1) in a crosswinding head of acrosswinding machine in bobbin (2) doffing operations according to claim2, characterized in that said interruption phase of the yarn (1) windingonto the bobbin (2) comprises the following sub-phase: stoppage of thebobbin (2) rotation.
 4. The process for the handling and control of theyarn (1) in a crosswinding head of a crosswinding machine in bobbin (2)doffing operations according to claim 2, characterized in that saidinterruption phase of the yarn (1) winding onto the bobbin (2) comprisesthe following sub-phases: cutting of the yarn (1), slowing down of therotation of the bobbin (2), rejoining of the two cut yarn (1) ends, andstoppage of the rotation of the bobbin (2).
 5. The process for thehandling and control of the yarn (1) in a crosswinding head of acrosswinding machine in bobbin (2) doffing operations according to claim1, characterized in that said movement phase of the yarn (1) run to adefinite position, is effected by positioning means present on eachcrosswinding head.
 6. The process for the handling and control of theyarn (1) in a crosswinding head of a crosswinding machine in bobbin (2)doffing operations according to claim 1, characterized in that saidmovement phase of the yarn (1) run to a definite position, is effectedby positioning means present on the service trolley (13).
 7. The processfor the handling and control of the yarn (1) in a crosswinding head of acrosswinding machine in bobbin (2) doffing operations according to claim1, characterized in that said movement phase of the yarn (1) run to adefinite position, is effected by positioning means situated on the backof the suction mouth (6) on the side of the bobbin and comprising thefollowing sub-phase: movement of the sucking (6) mouth on the side ofthe bobbin from its rest position, in correspondence with the joiningdevice (7), to the intervention position of the manipulating device(12), during the movement of the suction mouth (6), the yarn (1) beingengaged on its back in correspondence with said positioning means. 8.The process for the handling and control of the yarn (1) in acrosswinding head of a crosswinding machine in bobbin (2) doffingoperations according to claim 7, characterized in that during themovement phase of the suction mouth (6), the yarn (1) which is engagedon the back of the suction mouth (6) unravels from the pirn.
 9. Theprocess for the handling and control of the yarn (1) in a crosswindinghead of a crosswinding machine in bobbin (2) doffing operationsaccording to claim 7, characterized in that it comprises a return phaseof the suction mouth (6) to its rest position, following the collectionand cutting phase of the yarn (1) on the part of the manipulating device(12), during which the manipulating device (12) moves away from thecrosswinding head so as not to obstruct the movement of the suctionmouth (6).
 10. The process for the handling and control of the yarn (1)in a crosswinding head of a crosswinding machine in bobbin (2) doffingoperations according to claim 1, characterized in that the servicetrolley (13) is positioned in correspondence with the crosswinding headbefore the suction mouth (6) begins moving towards the bobbin (2). 11.The process for the handling and control of the yarn (1) in acrosswinding head of a crosswinding machine in bobbin (2) doffingoperations according to claim 1, characterized in that the servicetrolley (13) is positioned in correspondence with the crosswinding headafter the suction mouth (6) has reached the intervention position of themanipulating arm (12).
 12. A crosswinding machine comprising a series ofcrosswinding heads and at least one service trolley (13), each of saidcrosswinding heads comprising a pirn, from which a yarn (1) isunravelled and is wound around a bobbin (2), two mouths for the suctionof the yarn (1) ends possibly formed, by breakage or cutting, on theside of the pirn or on the side of the bobbin (2) respectively, and forthe delivery of these ends to a joining device (7), situated along therun of the yarn (1) from the pirn to the bobbin (2), to re-establish theyarn continuity, said service trolley (13) being capable of runningalong the whole crosswinding machine, in order to position itself incorrespondence with each crosswinding head and comprising a manipulationdevice (12) of the yarn (1) characterized in that it comprises means formoving the run of the yarn (1) to a definite position, close to theterminal portion of its course from the pirn to the bobbin (2), saidmeans being positioned on each crosswinding head or on the servicetrolley (13).
 13. The crosswinding machine according to claim 12,characterized in that said movement means of the course of the yarn (1)consist of an oscillating arm which engages the yarn (1) on its end, incorrespondence with a draft.
 14. The crosswinding machine according toclaim 12, characterized in that said movement means of the course of theyarn (1) consist of at least one draft, situated on the back of thesuction mouth (6).
 15. The crosswinding machine according to claim 14,characterized in that said means for the collection and positioning ofthe yarn (1) consist of two V-shaped drafts, a first draft (10) near thesucking inlet (8) of the suction mouth (6), substantially having thesame width as the inlet (8) of the suction mouth (6), and a second draft(11), near the oscillating arm (9) of the suction mouth (6).
 16. Asuction mouth (6) of a crosswinding machine, characterized in that ithas at least one draft on its back.
 17. The suction mouth (6) accordingto claim 16, characterized in that it has two drafts on its back, afirst draft (10) near the sucking inlet (8) of the suction mouth (6),substantially having the same width as the inlet (8) of the suctionmouth (6), and a second draft (11), near the oscillating arm (9) of thesuction mouth (6).